Iodine

Iodine sublimates into a beautiful violet vapor when heated: There's a torch under the plate in this photo. Iodine and iodine solutions were used as disinfectants before better antiseptic agents were found.

Tincture of iodine, smaller bottle.
And yet another small iodine bottle. I like this one, it's cute and the colors are nicer than the previous one, but the aspect ratio is not as good for a square photograph. Some day I will find the perfect iodine bottle.Source:eBay seller cynlionContributor:Theodore GrayAcquired:6 April, 2007Text Updated:6 April, 2007Price: $3Size: 2.5"Purity: 1%Sample Group:Medical

Iodigum, iodine chewing gum.
$33 for a pack of gum? Well, it's an interesting antique pack of gum, I guess that's why it got bid up that high by gum collectors. (How do I know it was bid up by gum collectors, not element collectors? Because on eBay you can see who else bid on the item, and then you can look at what other items they have won recently. The other bidders on this item had bid mostly on old gum, gum advertisements, gum promotional items, and lady's handbags. No elements.)
I, of course, was bidding on it because of its elemental content, iodine, and I won. These days goiter, a painful and unsightly swelling of the thyroid glands in the neck, is virtually unknown in developed countries, because of iodized salt. Pretty much any normal salt you buy has a bit of iodine added to it, and a bit is all you need to prevent goiter. But before the deployment of iodized salt (why they picked salt I'm not sure), goiter could be a problem for people living in parts of the world where the soil was naturally low in iodine, meaning that their local vegetables, etc, didn't contain much iodine. This gum was sold for people to chew as a preventative: Today there would be no point because it's virtually impossible to not get enough iodine in a typical diet.Source:eBay seller ddogmoxieContributor:Theodore GrayAcquired:20 January, 2007Text Updated:11 March, 2007Price: $33Size: 3"Purity: 1%Sample Group:Medical

This is a photograph I took for my Photographic Periodic Table Poster. The sample photograph includes text exactly as it appears in the poster, which you are encouraged to buy a copy of.

I took this photograph because my other black-background iodine photos were not good enough to go with all the other black-background pictures in the poster. I wanted to capture the beautiful purple smoke you get when iodine is gently heated. (The iodine pictured here is of course gone now, having evaporated during photography.)

Interesting fact about iodine vapor: You can't photograph it against a black background. Absolutely cannot be done, period. Now, photographing smoke against a black background is easy: Just shine light in from the side and some of it will be reflected towards the lens, resulting in bright smoke against a dark background. (Some of the prettiest smoke ever is in this story I wrote about making a light bulb.)

But iodine vapor is not smoke. Smoke consists of millions of very fine solid particles, each of which absorbs some light, reflects some, and diffracts some. However, iodine vapor, while it looks for all the world like purple smoke, is in fact a gas consisting of individual molecules of iodine, which can only absorb light, not reflect or diffract it. So any light entering it will either be absorbed, or will continue on in the same direction. Shining light on it from any angle will not result in any going towards the lens, unless the light is shining directly from the back into the lens, which of course is another way of saying that the background is light, not dark.

Colored gases are extremely uncommon. In everyday life, any time you see air that does not appear perfectly clear, it's because there is a particulate smoke of some sort in it. (Fog, for example, is a smoke of water droplets.) You virtually never see colored vapor that isn't smoke, so even though I should theoretically have know it was impossible, I spent about half an hour trying to pour more and more light into the side of my iodine vapor to make it show up against a pitch black background. Only after I had several thousand watt-seconds of studio flash light concentrated on it did I suddenly realize the complete futility of the exercise.

So now you know why iodine is one of very few samples in my poster that are not photographed against a black background.

Veterinary preparation.
Iodine is used as a disinfectant, or at least used to be. This vial contains 10 grams of resublimated iodine plus 3.5 grams of potassium iodide, and the label says it's from the "main veterinary place" in Berlin. It is said to be antique.Source:Frank LiebscherContributor:Frank LiebscherAcquired:28 January, 2004Text Updated:11 March, 2007Price: DonatedSize: 3"Purity: 93%Sample Group:Medical

Antique reagent bottle.
I first suspected something was up with iodine when I noticed that some of the eBay auctions for it were anonymous, a sure sign that there was something edgy going on. It only took a few minutes of research to determine the reason: It's used in the synthesis of methamphetamine (crystal meth). Just as you can't go and buy a dozen large bottles of Sudafed anymore, you can't buy too much iodine without raising eyebrows and perhaps a posse.

It's not in any sense illegal to buy, own, or transport any amount of iodine, just like it's not illegal to go into Walmart and buy 10,000 Sudafed pills. But watch out if you do: tracking people who do is one of the main ways meth labs are found, at least that's the way it seems from the frequent newspaper articles saying so-and-so was arrested outside of Walmart with six bottles of pseudoephedrine. Maybe he just had a really bad cold?

Antique iodine swabs.
I don't really know for sure, but I strongly suspect these are iodine dissolved in alcohol, packaged in a single-use swab designed to be used in a first aid kit. Presumably you break the capsule releasing the iodine solution, then use it to disinfect a cut.
If you know better, please straighten me out.Source:eBay seller suttonstContributor:Theodore GrayAcquired:3 May, 2003Text Updated:11 March, 2007Price: $5.50Size: 2"Purity: <5%Sample Group:Medical

Sample from the Everest Set.
Up until the early 1990's a company in Russia sold a periodic table collection with element samples. At some point their American distributor sold off the remaining stock to a man who is now selling them on eBay. The samples (except gases) weigh about 0.25 grams each, and the whole set comes in a very nice wooden box with a printed periodic table in the lid.

Sample from the RGB Set.
The Red Green and Blue company in England sells a very nice element collection in several versions. Max Whitby, the director of the company, very kindly donated a complete set to the periodic table table.

Tincture of Iodine (I and NaI in water/alcohol mixture).
Kindly contributed by Ed Pegg. William Kolb reports that the reason kids don't like iodine used as an antiseptic is not because iodine stings, but because the alcohol in which it is dissolved stings. How typical of the medical profession not to bother trying to find a better way to dissolve iodine, since alcohol is cheap and the only disadvantage is that it makes the patients scream. A bit of sodium iodide in the water is all it takes to allow iodine to dissolve without the need for alcohol, reports William's chemist friend.Source:Walgreens PharmacyContributor:Ed Pegg JrAcquired:20 May, 2002Text Updated:11 March, 2007Price: $5Size: 3"Purity: <5%Sample Group:Medical